首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   288篇
  免费   35篇
儿科学   11篇
妇产科学   1篇
基础医学   43篇
口腔科学   2篇
临床医学   30篇
内科学   74篇
皮肤病学   1篇
神经病学   3篇
特种医学   31篇
外科学   9篇
综合类   11篇
预防医学   21篇
药学   15篇
肿瘤学   71篇
  2022年   4篇
  2021年   4篇
  2017年   3篇
  2016年   3篇
  2015年   5篇
  2014年   14篇
  2013年   5篇
  2012年   15篇
  2011年   14篇
  2010年   10篇
  2009年   12篇
  2008年   16篇
  2007年   12篇
  2006年   6篇
  2005年   10篇
  2004年   10篇
  2003年   5篇
  2002年   8篇
  2001年   8篇
  2000年   5篇
  1999年   11篇
  1998年   9篇
  1997年   7篇
  1996年   3篇
  1995年   8篇
  1994年   8篇
  1993年   10篇
  1992年   3篇
  1990年   3篇
  1989年   5篇
  1988年   2篇
  1987年   4篇
  1986年   8篇
  1985年   4篇
  1984年   3篇
  1983年   3篇
  1982年   4篇
  1981年   5篇
  1980年   5篇
  1979年   3篇
  1978年   3篇
  1976年   6篇
  1975年   5篇
  1973年   2篇
  1971年   4篇
  1970年   6篇
  1968年   2篇
  1967年   2篇
  1963年   2篇
  1962年   2篇
排序方式: 共有323条查询结果,搜索用时 31 毫秒
31.
32.
Neoplasms with mixed carcinomatous and sarcomatous growth patterns occur in many organs and tissues. The pathogenesis of these cancers is thought to be either the result of two independent neoplastic processes merging to form a single tumor, or a neoplasm of monoclonal origin that develops phenotypic diversity. To address this issue, we characterized molecular alterations in separately microdissected epithelial and sarcomatous areas in three cases of pancreatic mucinous cystic neoplasms with sarcomatous stroma. Using microsatellite markers for six chromosomal loci commonly deleted in infiltrating ductal adenocarcinomas of the pancreas, we found genetic alterations to be virtually identical between the sarcomatous and epithelial components of two of the three neoplasms. In the third neoplasm, we found allelic losses and retentions to be identical at five of the six chromosomal loci, but at a single locus, we noted allelic loss in the neoplastic epithelial component but not the sarcomatous component. The same neoplasms were also analyzed for activating point mutations in codon 12 of the K-ras gene by using mutant-enriched polymerase chain reaction and allele-specific oligonucleotide hybridization. A K-ras mutation was identified in the epithelial component of one of the three neoplasms (the same tumor with an additional allelic loss in the neoplastic epithelial cells), but the sarcomatous component of this tumor was wild-type at codon 12 of K-ras, as were both components of the other two neoplasms. Overall, these results suggest a monoclonal origin with subsequent divergence of the neoplastic epithelial and sarcomatous portions of these neoplasms.  相似文献   
33.
34.
35.
Unrelated donor marrow transplantation in children   总被引:3,自引:10,他引:3  
Eighty-eight children 0.5 to 17 years of age (median, 9 years of age) received an unrelated donor marrow transplant for treatment of chronic myeloid leukemia (CML; n = 16), acute lymphoblastic leukemia (ALL) in first or second remission (n = 15) or more advanced stage (n = 28), acute myeloid leukemia (AML; n = 13), or other hematologic diseases (n = 16) between June 1985 and April 1993. All patients were conditioned with cyclophosphamide and total body irradiation and received a combination of methotrexate and cyclosporine as graft-versus-host disease (GVHD) prophylaxis. Fourty-six patients received transplants from HLA-identical donors and 42 patients received transplants from donors who were minor-mismatched at one HLA-A or B or D/DRB1 locus. The Kaplan-Meier estimates of disease-free survival and relapse were 75% and 0% for patients with CML, 47% and 20% for ALL in first or second remission, 10% and 60% for ALL in relapse or third remission, 46% and 46% for AML in first remission (n = 1) or more advanced disease (n = 12), and 29% and 69% for other diseases. HLA disparity was not significantly associated with lower disease-free survival, but the results suggest more relapses in HLA-matched recipients and there was significantly more transplant-related mortality in mismatched recipients (51% v 24%, P = .04). Most deaths were due to infections associated with acuteor chronic GVHD and occurred within the first 2 years after transplantation. Granulocyte engraftment occurred in all evaluable patients. Sixty-three percent of HLA-matched and 57% of HLA- mismatched recipients were discharged home disease-free at a median of 98 and 103 days, respectively, after transplantation (P = not significant [NS]). The incidence of grades II-IV acute GVHD was 83% in HLA-matched and 98% in HLA-mismatched recipients (P = .009). The incidence of chronic GVHD was 60% in HLA-matched and 69% in HLA- mismatched recipients (P = NS). One or multiple late adverse events such as cataracts, osteonecrosis of the hip or knee, restrictive or obstructive pulmonary disease, and hypothyroidism have occurred in 11 of 33 (33%) surviving patients. Immunosuppression was discontinued in 58% of surviving patients, including all 12 patients surviving more than 3.2 years, all of whom have a Lansky or Karnofsky score of 100%.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
36.
Non-Hodgkin's lymphoma (NHL) is the most common human immunodeficiency virus (HIV)-associated malignancy in hemophiliacs. We studied the incidence and clinicopathologic features of NHL in 3,041 hemophiliacs followed at 18 US Hemophilia Centers between 1978 and 1989. Of the 1,295 (56.6%) who were HIV(+), 253 (19.5%) developed acquired immunodeficiency syndrome (AIDS), of whom 14 (5.5%) developed NHL. Three NHL occurred in HIV(-) hemophiliacs, for a 36.5-fold greater risk in HIV(+) than HIV(-) hemophiliacs (P < .001). The NHL incidence rate was 29-fold greater than in the US population by Surveillance, Epidemiology, and End Results (SEER) estimates (P < .001). Between 0 and 4 lymphomas have been observed per year between 1978 and 1989. At presentation 13 (92.9%) of the HIV(+) NHL were extranodal. Ten were stage IV, 1 stage II, and 3 stage IE. Ten (71.4%) were high-grade, 3 (21.4%) intermediate-grade, and 1 (7.1%) was a low-grade B-cell lymphoma. Epstein-Barr virus (EBV) DNA was detected in 36% by in situ hybridization, including one central nervous system (CNS) lymphoma. The mean CD4 cell count at NHL diagnosis was 64/mm3, the mean latency from initial HIV infection was estimated to be 59 months, and the median survival was 7 months. The incidence of basal cell carcinoma in HIV(+) hemophiliacs was 18.3-fold greater than in HIV(-) hemophiliacs (P < .001) and 11.4-fold greater than in the US population (P < .001). In conclusion, incidence rates of NHL and basal cell carcinoma in HIV(+) hemophiliacs are significantly increased over rates in HIV(-) hemophiliacs and over rates in the US population. Clinicopathologic presentation of NHL in HIV(+) hemophiliacs is similar to that in HIV(+) homosexual men.  相似文献   
37.
38.
Host defense peptides, in particular LL-37, are emerging as potential therapeutics for promoting wound healing and inhibiting bacterial growth. However, effective delivery of the LL-37 peptide remains limiting. We hypothesized that skin-targeted electroporation of a plasmid encoding hCAP-18/LL-37 would promote the healing of wounds. The plasmid was efficiently delivered to full-thickness skin wounds by electroporation and it induced expression of LL-37 in the epithelium. It significantly accelerated reepithelialization of nondiabetic and diabetic wounds and caused a significant VEGFa and interleukin (IL)-6 induction. IL-6 was involved in LL-37–mediated keratinocyte migration in vitro and IL-6 neutralizing antibodies delivered to mice were able to suppress the wound healing activity of the hCAP-18/LL-37 plasmid. In a hindlimb ischemia model, electroporation of the hCAP-18/LL-37 plasmid increased blood perfusion, reduced muscular atrophy, and upregulated the angiogenic chemokines VEGFa and SDF-1a, and their receptors VEGF-R and CXCR-4. These findings demonstrate that a localized gene therapy with LL-37 is a promising approach for the treatment of wounds.  相似文献   
39.
Chemosensitivity of B lymphocytes, obtained from 65 patients with B- cell chronic lymphocytic leukemia (B-CLL), Rai stages 0 through IV, was determined using the MTT assay. The results were expressed by the drug concentration required for 50% inhibition of cell viability (IC50). The cytotoxicity of chlorambucil (CLB) was compared with that of fludarabine and the DNA topoisomerase I inhibitors, camptothecin, 9- aminocamptothecin, 10,11-methylenedioxy-20(S)-camptothecin (10,11-MDC) and 9-amino-10,11-methylenedioxy-20(S)-campthothecin (9-A-10,11-MDC), and topotecan. Considerable heterogeneity in sensitivity to CLB was observed, with a median IC50 of 40.5 mumol/L in untreated patients. B- CLL cells from patients treated with CLB had a significantly higher median IC50 of 86.0 mumol/L (P < .01). Untreated as well as CLB-treated patients were divided into two subsets. For the purpose of this study, B-CLL lymphocytes with an IC50 CLB of less than 61.0 mumol/L were designated as "sensitive" and those with an IC50 CLB of > or = 61.0 mumol/L were designated as "resistant." After baseline assays, 15 untreated patients received CLB; after treatment, the IC50 increased in B-CLL lymphocytes from 13 of 15 patients. The response to CLB treatment, determined by its effect on the absolute lymphocyte count and by the Eastern Cooperative Oncology Group clinical criteria, was significantly better in patients whose lymphocytes had an IC50 CLB of less than 61.0 mumol/L before therapy (P < .01). B-CLL lymphocytes also had a variable degree of sensitivity in vitro to each of the other drugs. There was significant cross-resistance between CLB and fludarabine (P < 0.01). Whereas only 29% of CLB-resistant B-lymphocyte specimens obtained from individual patients were sensitive to fludarabine in vitro, 52% and 67% of CLB-resistant lymphocyte samples were sensitive to 10,11-MDC and 9-A-10,11-MDC, respectively. We have previously reported that p53 gene mutations were associated with aggressive B-CLL and a poor prognosis. B lymphocytes from seven patients with these mutations were resistant to CLB, and five of six were resistant to fludarabine. Lymphocytes from four of seven were resistant to 10,11-MDC, and three of four were resistant to 9-A-10,11- MDC. This study implies that the MTT assay may be useful in identifying subsets of CLL patients resistant to conventional chemotherapy. However, definitive conclusions can not be drawn in view of the small number of patients studied prospectively. In addition, these results suggest the potential of camptothecin-based therapy for patients unresponsive to standard treatment.  相似文献   
40.
Despite matching for serologically defined HLA-A, B, DR antigens, acute graft-versus-host disease (GVHD) is a major complication contributing to increased morbidity and mortality in patients who undergo marrow transplantation from unrelated donors. The extent to which unrecognized mismatching for alleles that encode DR1-DR18 contribute to the increased risk of acute GVHD and overall survival is unknown. We analyzed 364 patients and their HLA-A, B, DR serologically matched donors to determine whether molecular typing of DRB1 alleles can allow more accurate donor/recipient matching and thereby improve clinical outcome after marrow transplantation. DRB1 alleles were typed by sequence-specific oligonucleotide probe hybridization methods. Selected alleles were confirmed by DNA sequencing. Of the 364 pairs, 305 were matched and 59 were mismatched for DRB1. The probability of moderate to severe acute GVHD was .48 for the matched and .70 for the mismatched patients. Compared with mismatched patients, the estimated relative risk (RR) of GVHD for matched patients was .58 (95% confidence interval [CI], .40 to .85). DRB1 matching decreased the risk of transplant- related mortality (RR, .66; 95% CI, .44 to .97) and was associated with decreased overall mortality (RR, .71; 95% CI, .51 to 1.0). Therefore, matching DRB1 alleles of the donor and recipient decreases the risk of acute GVHD and improves survival after unrelated marrow transplantation. These results indicate that prospective matching of patients and donors for DRB1 alleles is warranted.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号